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I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes.

I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users.

So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help.

GSBitConverter.cs

This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type.

public static class GSBitConverter
{
    public static byte[] ToGSBinary(this short value)
    {
        return BitConverter.GetBytes(value);
    }

    public static byte[] ToGSBinary(this IEnumerable<short> value)
    {
        List<byte> bytes = new List<byte>();
        short length = (short)value.Count();

        bytes.AddRange(length.ToGSBinary());
        for (int i = 0; i < length; i++)
            bytes.AddRange(value.ElementAt(i).ToGSBinary());

        return bytes.ToArray();
    }

    public static byte[] ToGSBinary(this bool value);
    public static byte[] ToGSBinary(this IEnumerable<bool> value);

    public static byte[] ToGSBinary(this IEnumerable<byte> value);

    public static byte[] ToGSBinary(this int value);
    public static byte[] ToGSBinary(this IEnumerable<int> value);

    public static byte[] ToGSBinary(this long value);
    public static byte[] ToGSBinary(this IEnumerable<long> value);

    public static byte[] ToGSBinary(this float value);
    public static byte[] ToGSBinary(this IEnumerable<float> value);

    public static byte[] ToGSBinary(this double value);
    public static byte[] ToGSBinary(this IEnumerable<double> value);

    public static byte[] ToGSBinary(this string value);
    public static byte[] ToGSBinary(this IEnumerable<string> value);

    public static string GetHexDump(this IEnumerable<byte> value);
}

Program.cs Here's the the object that I'm converting to binary in a loop.

class Program
{
    static void Main(string[] args)
    {
        GSObject obj = new GSObject();
        obj.AttachShort("smallInt", 15);
        obj.AttachInt("medInt", 120700);
        obj.AttachLong("bigInt", 10900800700);
        obj.AttachDouble("doubleVal", Math.PI);
        obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" });

        GSObject apple = new GSObject();
        apple.AttachString("name", "Apple");
        apple.AttachString("color", "red");
        apple.AttachBool("inStock", true);
        apple.AttachFloat("price", (float)1.5);

        GSObject lemon = new GSObject();
        apple.AttachString("name", "Lemon");
        apple.AttachString("color", "yellow");
        apple.AttachBool("inStock", false);
        apple.AttachFloat("price", (float)0.8);

        GSObject apricoat = new GSObject();
        apple.AttachString("name", "Apricoat");
        apple.AttachString("color", "orange");
        apple.AttachBool("inStock", true);
        apple.AttachFloat("price", (float)1.9);

        GSObject kiwi = new GSObject();
        apple.AttachString("name", "Kiwi");
        apple.AttachString("color", "green");
        apple.AttachBool("inStock", true);
        apple.AttachFloat("price", (float)2.3);

        GSArray fruits = new GSArray();
        fruits.AddGSObject(apple);
        fruits.AddGSObject(lemon);
        fruits.AddGSObject(apricoat);
        fruits.AddGSObject(kiwi);

        obj.AttachGSArray("fruits", fruits);

        Stopwatch w1 = Stopwatch.StartNew();
        for (int i = 0; i < 50000; i++)
        {
            byte[] b = obj.ToGSBinary();
        }
        w1.Stop();

        Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian");
        Console.WriteLine(w1.ElapsedMilliseconds + "ms");

    }

Here's the code for some of my other classes that are used in the code above. Most of it is repetitive.

GSObject

GSArray

GSWrappedObject

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3  
That is an enormous amount of code. TLDR. –  Byte56 Apr 2 '12 at 22:29
    
@Byte56 Yes I realize, but most of it is not relative, as it's repetition. I'm just showing the way I've organized things in case someone bothers to go through it all and can see where I'm losing preformance. –  Saad Imran. Apr 2 '12 at 22:31
1  
Post only the relevant code in the question. Link the rest, for those that want to look. –  Byte56 Apr 2 '12 at 22:33
    
@Byte56 Ok I will look for a place to post code where it can be viewed nicely for those that want to look through. Any suggestions? –  Saad Imran. Apr 2 '12 at 22:41
    
pastebin.com Is nice. And thanks! It'll make it a lot easier to answer the question. –  Byte56 Apr 2 '12 at 22:41
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2 Answers

I would use something like ProtoBuf with RPC support.

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1  
one issue with this is that OP seems to be using schemaless key-value pairs (i.e. more BSON-like than Protobuf) –  Jimmy Apr 2 '12 at 23:05
    
@RubberMallet I wanted to write my own code to make this a learning process, also I can't see a ActionScript library for protobuf. I plan on making various different client libraries so I would need my own code. –  Saad Imran. Apr 2 '12 at 23:10
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Without having read through all your code (or, indeed, being very familiar with .NET) and thus not knowing how appropriate this suggestion is:

Make a wrapper around a class like MemoryStream, and add methods to objects that need to be serialized/deserialized. Don't just make a class that's an arbitrary bag of data. If you have a Widget class, it might read and write something like this:

public void WriteToBinary(StreamWrapper stream)
{
    stream.WriteString(name);
    stream.WriteString(color);
    stream.WriteBool(inStock);
    stream.WriteFloat(price);
}

public void ReadFromBinary(StreamWrapper stream)
{
    name = stream.ReadString();
    color = stream.ReadString();
    inStock = stream.ReadBool();
    price = stream.ReadFloat();
}

This means never creating a temporary byte[] array that will always be thrown away. It also can lead to smaller messages, because you don't need to encode the name of every single property: the order of reading/writing can disambiguate.

share|improve this answer
    
Thanks for the suggestion, the classes aren't really a bag of data. They're custom objects that will be used heavily (in object form) on both the client and server side, the only time I would be converting to binary is to send through the socket and to read from it. But yea, I will look into streams. –  Saad Imran. Apr 2 '12 at 23:13
    
In that case, yeah, don't make a class whose only purpose is to hold a bag of properties before they get turned into binary. It'll be less efficient, lead to larger messages, and lose customizability. Those intermediate objects, plus a byte[] object per field, could add up fast. I dunno if that would actually be your bottleneck, but I could easily see that being the case. –  John Calsbeek Apr 2 '12 at 23:16
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